Brain stem control of the phases of swallowing

Modulation of Pharyngoesophageal Motility Characteristics During Concurrent Oral Feeding in Infants: Novel Pilot Observations

Effect of interventions or diseases on the mechanisms of swallowing difficulties, and indications to change nipples, flows, or formula thickness in high-risk infants remains unclear. We evaluated and compared the effects of nipple flows and/or formula thickness on pharyngoesophageal timing and amplitude characteristics during oral milk challenge (OMC). A total of 48 OMC trials were undertaken in 12 infants [born at 36.4 ± 3.8 weeks gestation, studied at 48.0 ± 5.6 weeks postmenstrual age (PMA)] concurrent with high resolution pharyngoesophageal manometry (HRPM). We evaluated timing and amplitude of swallowing characteristics (pharyngeal and esophageal contractile strength, duration, activity, pharyngeal peak interval variability, bursts, and rhythm) and volume intakes. We compared within and between the entities: un-thickened formula vs. thickened formula and slower- vs. faster flow nipple. OMC durations averaged 71 ± 31 s and did not differ between interventions (p > 0.05). Pharyngeal swallow rhythms (timing) and contractile characteristics were dependent on the interaction between nipple flow rates and formula thickness (p < 0.05). Thickness decreased overall contractility and modified distal pharyngeal contractile activity (p < 0.05), which is critical to opening the upper esophageal sphincter. A structural equation model was developed that revealed the influence of PMA, respiratory status, volume extracted, nipple flow rate, and thickener presence on pharyngeal swallowing frequency with a comparative fit index of 0.83. Oropharyngeal stimulus-types trigger, integrate, and modify brainstem mediated oral and pharyngeal rhythms and modulate contractility and airway protection mechanisms. Effects of therapies, maturation and diagnoses are measurable using these novel approaches at crib-side.

A novel approach using acupuncture for dysphagia after brainstem stroke: A CARE-compliant case report

BACKGROUND

Dysphagia is a common sequela of brainstem stroke, often leading to complications such as aspiration pneumonia and malnutrition. Traditional rehabilitation methods may not be effective for all patients, necessitating alternative therapeutic approaches. Herein, we report a case of acupuncture for dysphagia after brainstem stroke.

CASE DESCRIPTION

In this report, we describe a 61-year-old male patient with persistent dysphagia, aspiration during water intake, and hoarseness following acute brainstem infarction. Despite undergoing thrombolysis and rehabilitation, his swallowing function remained unimproved. A videofluoroscopic swallowing study (VFSS) demonstrated substantial barium residue in bilateral valleculae and pyriform sinuses with significant aspiration. The patient received 14 days of acupuncture therapy, combining electrical stimulation at primary acupoints in the cephalocervical region with rapid needling techniques at extraordinary points in the cervical area. Post-treatment evaluation revealed remarkable improvement in swallowing function with complete resolution of aspiration, enabling nasogastric tube removal. Three-month follow-up confirmed sustained normal swallowing function without recurrence.

CONCLUSION

The innovative acupuncture treatment regimen we proposed may be a promising therapeutic option for dysphagia after brainstem stroke.

Age-defying swallowing

Swallowing disorders, which are generally underdiagnosed, affect the elderly, leading to a decreased quality of life and complications, including aspiration pneumonia and death. Understanding the neurophysiology of swallowing and the causes of its dysfunction is a fundamental tool for the prevention, early diagnosis, and treatment of dysphagia. New technologies open a wide range of possibilities for the implementation of new care protocols for this disorder.

Effect of acute ethanol intoxication on swallowing function in mice

OBJECTIVES

Ethanol consumption may lead to various symptoms depending on its concentration in the blood. Acute ethanol intoxication is a major risk factor for bolus -aspiration; however, studies on the effects of acute ethanol intoxication on swallowing are lacking. Therefore, we investigated the effect of acute ethanol intoxication on mice using the videofluoroscopic swallowing study (VFSS) methodology.

METHODS

Male C57BL/6 J mice were randomly allocated into three groups: saline injection, 2 g/kg ethanol injection, and 4 g/kg ethanol injection. The VFSS technique was used to analyze the inter-swallow interval, lick-swallow rate, lick rate, bolus area, pharyngeal transit time, bolus speed, and bolus area 3 d before injection (control), 2 h after injection, and 8 h after injection.

RESULTS

In the 4 g/kg ethanol injection group, the inter-swallow interval and lick-swallow rate increased after 2 h However, these changes were reversed 8 h after ethanol administration. Additionally, the pharyngeal transit time, bolus speed, and bolus area did not change significantly after ethanol administration.

CONCLUSIONS

The present study reveals that ethanol administration delays bolus transport in the mouth but does not affect pharyngeal swallowing reflexes and reflex thresholds. Acute ethanol intoxication specifically impairs the oral function as assessed by the VFSS.

Post-stroke dysphagia: Neurological regulation and recovery strategies

Swallowing is a complex process requiring precise coordination of numerous muscles in the head and neck to smoothly guide ingested material from the mouth to the stomach. Animal and human studies have revealed a complex network of neurons in the brainstem, cortex, and cerebellum that coordinate normal swallowing. The interactions between these regions ensure smooth and efficient swallowing. However, the current understanding of the neurophysiological mechanisms involved in post-stroke dysphagia (PSD) is incomplete, and complete functional connectivity for swallowing recovery remains understudied and requires further exploration. In this review, we discussed the neuroanatomy of swallowing and the pathogenesis of PSD and summarized the factors affecting PSD recovery. We also described the plasticity of neural networks affecting PSD, including enhancing activation of neural pathways, cortical reorganization, regulation of extracellular matrix dynamics and its components, modulation of neurotransmitter delivery, and identification of potential therapeutic targets for functional recovery in PSD. Finally, we discussed the therapeutic strategies based on functional compensation and motor learning. This review aimed to provide a reference for clinicians and researchers to promote the optimization of PSD treatments and explore future research directions.

Dysphagia

Dysphagia, or difficulty swallowing, has significant impacts on patients' quality of life. A thorough history and physical examination can provide important information to determine if dysphagia is originating from oropharyngeal or esophageal causes. Identifying the underlying pathology contributing to dysphagia allows for optimal treatment and improved quality of life.

Predictors of recovery from dysphagia after stroke: A systematic review and meta-analysis

Objective

This systematic review aimed to identify the predictors of recovery from dysphagia after stroke in the last ten years, thereby providing an evidence-based basis for nurses to identify high-risk patients and develop individualized rehabilitation plans to improve patient prognosis.

Methods

Databases including the China National Knowledge Infrastructure (CNKI), China Biology Medicine disc (CBMdisc), China Science and Technology Journal (VIP), WanFang, PubMed, Embase, CINAHL, Web of Science, the Cochrane Library, and Scopus were retrieved to search for literature on the predictors of recovery from dysphagia after stroke. The retrieval period was from January 2013 to December 2023. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS) and the Prediction model Risk of Bias Assessment Tool (PROBAST). Meta-analysis was performed using Revman5.3 and Stata15.1 software. The review protocol has been registered with PROSPERO (CRD42024605570).

Results

A total of 1,216 results were obtained, including 599 in English and 617 in Chinese. A total of 34 studies were included, involving 156,309 patients with post-stroke dysphagia, and the rate of dysphagia recovery increased from 13.53% at 1 week to 95% at 6 months after stroke. Meta-analysis results showed that older age [OR = 1.06, 95%CI (1.04, 1.08), P < 0.001], lower BMI [OR = 1.28, 95%CI (1.17, 1.40), P < 0.001], bilateral stroke [OR = 3.10, 95%CI (2.04, 4.72), P < 0.001], higher National Institutes of Health Stroke Scale (NIHSS) score [OR = 1.19, 95%CI (1.01, 1.39), P = 0.030], tracheal intubation [OR = 5.08, 95%CI (1.57, 16.39), P = 0.007] and aspiration [OR = 4.70, 95%CI (3.06, 7.20), P < 0.001] were unfavorable factors for the recovery of swallowing function in patients with post-stroke dysphagia.

Conclusions

The lack of standardized criteria for rehabilitation assessment of post-stroke dysphagia has resulted in reported recovery rates of swallowing function exhibiting wide variability. Nurses should take targeted preventive measures for patients aged ≥70 years, low BMI, bilateral stroke, high NIHSS score, tracheal intubation, and aspiration to promote the recovery of swallowing function in patients with post-stroke dysphagia.

Assessing the Effect of Fatigue on Swallowing Function in Adults with Acute Stroke. A Pilot Study

Objective

To determine if fatigue systematically effects the timing of swallowing events and to discuss underlying causes of fatigue other than peripheral neuromuscular fatigue.

Design

Pre-post within-subject repeated-measures design.

Setting

General acute care hospital and designated stroke center.

Participants

Thirteen patients (10 males and 3 females) aged 52-80 years (mean 64.84±9.58 y) with acute stroke and clinically suspected dysphagia.

Interventions

Under videofluoroscopy, each participant swallowed a pre- and post-study 1-mL liquid barium bolus and, in an attempt to fatigue the system, 30-45 additional bolus trials of varying amounts (ie, 5 mL, 10 mL, and bite-sized) and consistencies (ie, International Dysphagia Diet Standardisation Initiative Level 0-7).

Main Outcome Measures

Six temporal sequences (ie, oral, pharyngeal, and pharyngeal delay transit times and durations of laryngeal vestibule closure, cricopharyngeal opening, and laryngeal elevation) for 1-mL liquid boluses were measured pre- and postvideofluoroscopic swallowing study and compared.

Results

Findings indicated that only 2 of the 6 temporal factors yielded significant differences pre- to post fatigue. The postvideofluoroscopic 1-mL liquid swallow took longer than the pre-videofluoroscopic 1-mL liquid swallow in terms of pharyngeal transit (1,11=5.362, P=.046) and pharyngeal delay time (F 1,11=5.228, P=.048).

Conclusions

These findings indicate that peripheral neuromuscular fatigue is unlikely to be the primary cause of the observed changes, as only 2 of the 6 temporal measures-pharyngeal transit time and pharyngeal delay time-were affected. In cases of peripheral neuromuscular fatigue, one would expect increases across all 6 timing measures due to the integrated nature of the swallowing process. Instead, the results suggest that the inconsistencies may stem from a delayed excitatory response of neurons or a delay in synaptic transmission within the nucleus tractus solitarius, potentially associated with stroke. This delay likely contributes to the prolongation of both pharyngeal transit and pharyngeal delay times. Thus, a model focused solely on peripheral neuromuscular fatigue does not fully account for the findings, highlighting the importance of considering central neural mechanisms in the clinical evaluation of swallowing disorders.

Speech-Swallow Dissociation of Velopharyngeal Incompetence with Pseudobulbar Palsy: Evaluation by High-Resolution Manometry

Patients with pseudobulbar palsy often present with velopharyngeal incompetence. Velopharyngeal incompetence is usually observed during expiratory activities such as speech and/or blowing during laryngoscopy. These patients typically exhibit good velopharyngeal closure during swallowing, which is dissociated from expiratory activities. We named this phenomenon "speech-swallow dissociation" (SSD). SSD on endoscopic findings can help in diagnosing the underlying disease causing dysphagia. This endoscopic finding is qualitative, and the quantitative characteristics of SSD are still unclear. Accordingly, the current study aimed to quantitatively evaluate SSD in patients with pseudobulbar palsy. We evaluated velopharyngeal pressure during swallowing and expiratory activity in 10 healthy subjects and 10 patients with pseudobulbar palsy using high-resolution manometry, and compared the results between the two groups. No significant differences in maximal velopharyngeal contraction pressure (V-Pmax) were observed during dry swallowing between the pseudobulbar palsy group and healthy subjects (190.5 mmHg vs. 173.6 mmHg; P = 0.583). V-Pmax during speech was significantly decreased in the pseudobulbar palsy group (85.4 mmHg vs. 34.5 mmHg; P < 0.001). The degree of dissociation of speech to swallowing in V-Pmax, when compared across groups, exhibited a larger difference in the pseudobulbar palsy group, at 52% versus 80% (P = 0.001). Velopharyngeal pressure during blowing was similar to that during speech. Velopharyngeal closure in patients with pseudobulbar palsy exhibited weaker pressure during speech and blowing compared with swallowing, quantitatively confirming the presence of SSD. Pseudobulbar palsy often presents with SSD, and this finding may be helpful in differentiating the etiology of dysphagia.

Coordination of Pharyngeal and Esophageal Phases of Swallowing

Although swallowing has been reviewed extensively, the coordination of the phases of swallowing have not. The phases are controlled by the brainstem, but peripheral factors help coordinate the phases. The occurrence, magnitude, and duration of esophageal phase depends upon peripheral feedback activated by the bolus. The esophageal phase does not occur without peripheral feedback from the esophagus. This feedback is mediated by esophageal slowly-adapting mucosal tension receptors through the recurrent and superior laryngeal nerves. A similar reflex mediated by the same peripheral pathway is the activation of swallowing by stimulation of the cervical esophagus. This reflex occurs primarily in human infants and animals, and this reflex may be important for protecting against aspiration after esophago-pharyngeal reflux. Not only are there inter-phase excitatory processes, but also inhibitory processes. A significant inhibitory process is deglutitive inhibition. When one swallows faster than peristalsis ends, peristalsis is inhibited by the new pharyngeal phase. This process prevents the ongoing esophageal peristaltic wave from blocking the bolus being pushed into the esophagus by the new wave. The esophageal phase returns during the last swallow of the sequence. This process is probably mediated by mucosal tension receptors through the superior laryngeal nerves. A similar reflex exists, the pharyngo-esophageal inhibitory reflex, but studies indicate that it is controlled by a different neural pathway. The pharyngo-esophageal inhibitory reflex is mediated by mucosal tension receptors through the glossopharyngeal nerve. In summary, there are significant peripheral processes that contribute to swallowing, whereby one phase of swallowing significantly affects the other.

Serotonergic modulation of swallowing in a complete fly vagus nerve connectome

How the body interacts with the brain to perform vital life functions, such as feeding, is a fundamental issue in physiology and neuroscience. Here, we use a whole-animal scanning transmission electron microscopy volume of Drosophila to map the neuronal circuits that connect the entire enteric nervous system to the brain via the insect vagus nerve at synaptic resolution. We identify a gut-brain feedback loop in which Piezo-expressing mechanosensory neurons in the esophagus convey food passage information to a cluster of six serotonergic neurons in the brain. Together with information on food value, these central serotonergic neurons enhance the activity of serotonin receptor 7-expressing motor neurons that drive swallowing. This elemental circuit architecture includes an axo-axonic synaptic connection from the glutamatergic motor neurons innervating the esophageal muscles onto the mechanosensory neurons that signal to the serotonergic neurons. Our analysis elucidates a neuromodulatory sensory-motor system in which ongoing motor activity is strengthened through serotonin upon completion of a biologically meaningful action, and it may represent an ancient form of motor learning.

Relevance of ineffective esophageal motility to striated esophageal muscle contraction: Studies with high-resolution manometry

Striated esophageal muscle contraction (SEC) is important for pharyngeal swallowing and deglutition augmentation against aspiration. Its clinical relevance is unclear in patients with ineffective esophageal motility (IEM). In this study, we aimed to characterize and compare SEC in consecutive patients with and without IEM. All eligible patients were evaluated for SEC, primary and secondary peristalsis using high-resolution manometry (HRM) with one mid-esophageal injection port. Primary peristalsis was assessed with 10 5-mL liquid swallows and multiple rapid swallows (MRS), while secondary peristalsis was performed with rapid air injections of 20 mL. All peristatic parameters of HRM were measured, and SEC and its contractile integral (SECI) were evaluated. One hundred and forty patients (59.3% women, mean age 46.1 ± 13.1 years) were included. There was no difference in SECI between patients with and without IEM (p = 0.91). SECI was also similar between patients with and without secondary peristalsis for IEM (p = 0.63) or normal motility (p = 0.80). No difference in SECI was seen between patients with and without MRS for IEM (p = 0.55) or normal motility (p = 0.88). SECI was significantly higher in male patients than female patients in IEM patients (p = 0.01). SECI significantly correlated with age in patients with normal motility (r = -0.31, p = 0.01). Aging may have a negative impact on SEC in patients with normal motility, while gender difference in SECI occurs in IEM patients. Neither secondary peristalsis nor MRS influences SECI.

Comparison between botulinum toxin type A injection on masseter muscle only and additional injection on anterior belly of digastric muscle in sleep bruxism patients: A clinical trial

OBJECTIVE

This study aims to evaluate the effects on bite force and muscle thickness of the botulinum toxin (BoNT) injection for patients with sleep bruxism (SB) by comparing injections into the masseter muscle only and both the masseter and the anterior belly of the digastric muscle (ABDM) in a clinical trial.

METHODS

Twelve SB patients received BoNT-A injections using US-guided techniques into the masseter muscle only (Group A), while the remaining 12 SB patients received injections into both the masseter and ABDM (Group B). Bite force and muscle thickness were measured before injection, as well as 1 and 2 months after injection.

RESULTS

The bite force and masseter muscle thickness decreased in both Group A and Group B before injection, and at 1 and 2 months after injection. However, there was no significant difference (p > .05, repeated measures analysis of variance) between the two groups, and there was also no significant difference in ABDM thickness (p > .05, repeated measures analysis of variance).

CONCLUSION

This study is the first to assess the short-term effects of BoNT injected into ABDM for SB control. Results show no influence on SB reduction, suggesting the need for further research on BoNT's effectiveness in controlling intense ABDM contractions during sleep and assessing suprahyoid muscle potential impact on rhythmic masticatory muscle activity occurrence.

A Review of In Vitro and In Silico Swallowing Simulators: Design and Applications

Swallowing is a primary and complex behaviour that transports food and drink from the oral cavity, through the pharynx and oesophagus, into the stomach at an appropriate rate and speed. To understand this sophisticated behaviour, a tremendous amount of research has been carried out by utilising the in vivo approach, which is often challenging to perform, poses a risk to the subjects if interventions are undertaken and are seldom able to control for confounding factors. In contrast, in silico (computational) and in vitro (instrumental) methods offer an alternate insight into the process of the human swallowing system. However, the appropriateness of the design and application of these methods have not been formally evaluated. The purpose of this review is to investigate and evaluate the state of the art of in vitro and in silico swallowing simulators, focusing on the evaluation of their mechanical or computational designs in comparison to the corresponding swallowing mechanisms during various phases of swallowing (oral phase, pharyngeal phase and esophageal phase). Additionally, the potential of the simulators is also discussed in various areas of applications, including the study of swallowing impairments, swallowing medications, food process design and dysphagia management. We also address current limitations and recommendations for the future development of existing simulators.

Use of Pinching Nose Maneuver in a Patient With Severe Dysphagia Caused by Pseudobulbar Palsy

Swallowing disorders resulting from pseudobulbar palsy are characterized by deficiencies in the oral preparatory and oral stages of the swallowing process. In certain cases, obstruction can occur when the tongue base comes into contact with the palate, impeding the intraoral bolus flow into the pharyngeal cavity. In this report, we discuss a case of severe pseudobulbar palsy, in which an intraoral bolus flowed into the pharyngeal cavity with pinching the nose. A 78-year-old man with a history of recurrent cerebral infarction was evaluated. The patient had severe dysphagia and cognitive impairment due to pseudobulbar palsy. A videofluoroscopic examination of swallowing (VF) was conducted while the patient was in a reclined position. In the oral cavity, when the bolus reached the posterior tongue section, the flow was hindered by the functional obstruction caused by the tongue base pressing against the palate. Despite the clinician's instructions to swallow, the patient was unable to comply due to the severity of his cognitive impairment. To alleviate this obstruction, the clinician pinched the patient's nose. This action opened the fauces, facilitating breathing and relieving the functional obstruction. Subsequently, the bolus flowed into the pharyngeal cavity and successfully flowed into the esophagus while swallowing. This maneuver was named the "pinching nose maneuver" (PNM). The PNM, as described here, can serve as a technique to improve the movement of an intraoral bolus into the pharyngeal cavity in patients with cognitive dysfunction.

Swallowing dysfunctions in patients with disorders of consciousness: Evidence from neuroimaging data, assessment, and management

Following severe brain injuries, a subset of patients may remain in an altered state of consciousness; most of these patients require artificial feeding. Currently, a functional oral phase and the presence of exclusive oral feeding may constitute signs of consciousness. Additionally, the presence of pharyngo-laryngeal secretions, saliva aspiration, cough reflex and tracheostomy are related to the level of consciousness. However, the link between swallowing and consciousness is yet to be fully understood. The primary aim of this review is to establish a comprehensive overview of the relationship between an individual's conscious behaviour and swallowing (reflexive and voluntary). Previous studies of brain activation during volitional and non-volitional swallowing tasks in healthy subjects are also reviewed. We demonstrate that the areas activated by voluntary swallowing tasks (primary sensorimotor, cingulate, insula, premotor, supplementary motor, cerebellum, and operculum) are not specific to deglutitive function but are shared with other motor tasks and brain networks involved in consciousness. This review also outlines suitable assessment and treatment methods for dysphagic patients with disorders of consciousness. Finally, we propose that markers of swallowing could contribute to the development of novel diagnostic guidelines for patients with disorders of consciousness.

Postoperative Measurement of the Retropharyngeal Space Predicts the Risk of Dysphagia After Anterior Cervical Diskectomy and Fusion

BACKGROUND AND OBJECTIVES

Postoperative dysphagia is a common complication of anterior cervical diskectomy and fusion (ACDF), although its pathophysiology remains poorly understood. Patients with severe dysphagia may suffer from serious complications such as aspiration pneumonia, in addition to difficulty with oral intake or malnutrition; therefore, a prompt indicator for postoperative management would be helpful. We quantitatively evaluated the retropharyngeal space (RS) after ACDF and investigated its association with postoperative dysphagia.

METHODS

This multicenter retrospective study analyzed the clinical data of 82 consecutive patients who underwent ACDF. The anteroposterior distance (APD) of the RS was measured at the C2 level using a lateral radiographic view on postoperative day 1. Postoperative dysphagia was subjectively assessed using the Bazaz-Yoo Dysphagia Severity Scale. We statistically evaluated the association between the APD of the RS and postoperative dysphagia.

RESULTS

The mean APD of the RS in all 82 patients was 3.6 mm preoperatively and significantly increased to 8.2 mm postoperatively (P < .0001). Twenty-two patients (26.8%) had postoperative dysphagia. Multivariable analysis revealed that the postoperative APD was associated with postoperative dysphagia (odds ratio 1.27, 95% CI 1.10-1.50, P = .0007). The receiver operating characteristic curve (area under the curve 0.70, 95% CI 0.58-0.83) demonstrated that the postoperative APD of the RS cutoff value was 6.1 mm, with a sensitivity of 100% and a specificity of 35%. With this cutoff value, the positive and negative predictive values for postoperative dysphagia were 36% and 100%, respectively.

CONCLUSION

Our data demonstrate that a value of 6.1 mm for the APD of the RS is an effective indicator for dysphagia after ACDF, which contributes to optimizing the patient management in the acute postoperative period.

Effects of suprahyoid muscle strengthening exercise using kinesiology taping on muscle activation and thickness in community-dwelling elderly: A randomized controlled trial

BACKGROUND

Recently, swallowing resistive exercise using kinesiology taping (KT) has been reported as a novel method for dysphagia rehabilitation However, clinical evidence is still unclear, and effects in the elderly have not been confirmed.

OBJECTIVE

This study aimed to investigate the effects of suprahyoid muscle strengthening exercise using KT on muscle activation and thickness in community-dwelling elderly.

METHODS

A total of 24 healthy older people were enrolled in this study and randomly assigned to an experimental group and a placebo group. In the experimental group, KT was attached to the front of the neck with a tension of about 70% to 80%, and a resistive swallowing exercise was performed. In the placebo group, the tape was applied similarly but without tension. Both groups performed resistive swallowing exercises 10 times a day (50 swallows per day) for 6 weeks. The activation and thickness of the suprahyoid muscles were measured using portable ultrasound equipment and an surface electromyelograph device.

RESULTS

The experimental group showed a significant increase in suprahyoid muscle activation (mean and peak) and muscle thickness (digastric and mylohyoid) than the placebo group (all, P < .05).

CONCLUSION

This study confirmed that suprahyoid muscle strengthening exercise using KT had a positive effect on the suprahyoid muscles in healthy older adults, thus suggesting the possibility of a therapeutic exercise method for dysphagia rehabilitation.

Chairside transformation of a removable partial denture to a transitional complete denture to alleviate an impaired stroke patient: A case report

BACKGROUND

The purpose of this clinical report is to present a technique for transformation of an existing removable partial denture (RPD) into a transitional complete denture (CD) for an impaired stroke patient.

CASE PRESENTATION

A 67-year-old male who underwent an ischemic stroke 12 months ago presented in the Postgraduate Clinic of the National and Kapodistrian University of Athens, requiring treatment of his remaining teeth and repair of his existing RPD which lacked retention and stability. The treatment plan included placement of amalgam plugs on the remaining teeth which were decoronated due to poor prognosis and modification of the existing RPD to a transitional CD. The procedure included one alginate impression and chairside alteration of the prosthesis with simple means. The new prosthesis managed to improve patient's masticatory ability and reduce the risk for aspiration pneumonia.

CONCLUSION

In the present case report a technique for modifying an existing RPD into a transitional CD for an impaired, stroke patient is described. Reduced treatment time, costs and patient's inconvenience while embracing the benefits provided by the utilization of an existing prosthesis regarding adaptation of the neuromuscular system are among the advantages of the described technique.

[Dysphagia in Parkinsonian Syndromes]

Dysphagia is a clinically relevant problem in Parkinson's disease as well as in atypical Parkinsonian syndromes, such as multiple system atrophy and diseases from the spectrum of 4‑repeat tauopathies, which affect most patients to a varying degree in the course of their disease. This results in relevant restrictions in daily life due to impaired intake of food, fluids, and medication with a subsequent reduction in quality of life. This article not only gives an overview of the pathophysiological causes of dysphagia in the various Parkinson syndromes, but also presents screening, diagnostic and treatment procedures that have been investigated for the different diseases.

Prox2 and Runx3 vagal sensory neurons regulate esophageal motility

Vagal sensory neurons monitor mechanical and chemical stimuli in the gastrointestinal tract. Major efforts are underway to assign physiological functions to the many distinct subtypes of vagal sensory neurons. Here, we use genetically guided anatomical tracing, optogenetics, and electrophysiology to identify and characterize vagal sensory neuron subtypes expressing Prox2 and Runx3 in mice. We show that three of these neuronal subtypes innervate the esophagus and stomach in regionalized patterns, where they form intraganglionic laminar endings. Electrophysiological analysis revealed that they are low-threshold mechanoreceptors but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis in freely behaving mice. Our work defines the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain and could lead to better understanding and treatment of esophageal motility disorders.

Feasibility study of the Nox-T3 device to detect swallowing and respiration pattern in neurologically impaired patients in the acute phase

Dysphagia is a frequent complication in neurologically impaired patients, which can lead to aspiration pneumonia and thus prolonged hospitalization or even death. It is essential therefore, to detect and assess dysphagia early for best patient care. Fiberoptic endoscopic and Videofluoroscopy evaluation of swallowing are the gold standard exams in swallowing studies but neither are perfectly suitable for patients with disorders of consciousness (DOC). In this study, we aimed to find the sensitivity and specificity of the Nox-T3 sleep monitor for detection of swallowing. A combination of submental and peri-laryngeal surface electromyography, nasal cannulas and respiratory inductance plethysmography belts connected to Nox-T 3 allows recording swallowing events and their coordination with breathing, providing time-coordinated patterns of muscular and respiratory activity. We compared Nox-T3 swallowing capture to manual swallowing detection on fourteen DOC patients. The Nox-T3 method identified swallow events with a sensitivity of 95% and a specificity of 99%. In addition, Nox-T3 has qualitative contributions, such as visualization of the swallowing apnea in the respiratory cycle which provide additional information on the swallowing act that is useful to clinicians in the management and rehabilitation of the patient. These results suggest that Nox-T3 could be used for swallowing detection in DOC patients and support its continued clinical use for swallowing disorder investigation.

Synaptic loss and gliosis in the nucleus tractus solitarii with streptozotocin-induced Alzheimer's disease

Obstructive sleep apnea is highly prevalent in Alzheimer's disease (AD). However, brainstem centers controlling respiration have received little attention in AD research, and mechanisms behind respiratory dysfunction in AD are not understood. The nucleus tractus solitarii (nTS) is an important brainstem center for respiratory control and chemoreflex function. Alterations of nTS integrity, like those shown in AD patients, likely affect neuronal processing and adequate control of breathing. We used the streptozotocin-induced rat model of AD (STZ-AD) to analyze cellular changes in the nTS that corroborate previously documented respiratory dysfunction. We used 2 common dosages of STZ (2 and 3 mg/kg STZ) for model induction and evaluated the early impact on cell populations in the nTS. The hippocampus served as control region to identify site-specific effects of STZ. There was significant atrophy in the caudal nTS of the 3 mg/kg STZ-AD group only, an area known to integrate chemoafferent information. Also, the hippocampus had significant atrophy with the highest STZ dosage tested. Both STZ-AD groups showed respiratory dysfunction along with multiple indices for astroglial and microglial activation. These changes were primarily located in the caudal and intermediate nTS. While there was no change of astrocytes in the hippocampus, microglial activation was accompanied by a reduction in synaptic density. Together, our data demonstrate that STZ-AD induces site-specific effects on all major cell types, primarily in the caudal/intermediate nTS. Both STZ dosages used in this study produced a similar outcome and can be used for future studies examining the initial symptoms of STZ-AD.

Effect of transcutaneous auricular vagus nerve stimulation on post-stroke dysphagia

BACKGROUND AND PURPOSE

It has been proved that electrical vagus nerve stimulation can promote the recovery of motor function after stroke. There were no trials on the use of transcutaneous auricular electrical vagus nerve stimulation (ta-VNS) in patients with dysphagia after acute stroke. Our aim was to confirm whether ta-VNS can promote the recovery of swallowing function in these acute stroke patients with dysphagia.

METHODS

We conducted a sham-controlled, double-blinded, parallel pilot study in 40 acute stroke patients randomly assigned to receive ta-VNS or sham ta-VNS combined with conventional rehabilitation training. The intensity of ta-VNS treatment was adjusted according to the patient's tolerance, 30 min each time, twice a day, five times a week, with a total course of 3 weeks. In the sham group, the parameters were the same except energy output. Swallowing function was assessed with Modified Mann assessment of swallowing ability (MASA), functional communication measure swallowing test (FCM), and the Rosenbek leakage/aspiration scale (RAS) according to swallowing video fluoroscopic (SVF) before the intervention (baseline, T0), immediately after the intervention (T1) and 4 weeks after the intervention (T2).

RESULTS

After treatment, ta-VNS group statistically and clinically had larger change of MASA, FCM, and RAS scores compared with control group (P < 0.05) and this improvement continued at least 4 weeks after the end of treatment. There were no serious adverse events occurred during the whole intervention.

CONCLUSION

The transcutaneous auricular electrical vagus nerve stimulation is effective as a novel and noninvasive treatment strategy for patients with dysphagia after acute stroke.

TRIAL REGISTRATION

No: kelunshen No. 63 in 2020.

A biomechanical response of the esophagus participates in swallowing

Evidence suggests that a biomechanical process participates in esophageal function, but no such function has yet been identified. We investigated the role of a biomechanical process during swallowing in 30 decerebrate cats instrumented using electromyogram (EMG) electrodes, strain gauge force transducers, and manometry. We found that the cervical esophagus has a short-lasting circumferential tension response during the pharyngeal phase of swallowing (CTPP), and a concomitant EMG response. The CTPP magnitude was correlated with magnitudes of contraction of the geniohyoideus, laryngeal elevation force, and esophageal orad elongation force. The magnitude of the CTPP was not correlated with the peak or area under the curve of the concomitant esophageal EMG response. Restricting laryngeal elevation by physical force or transecting the hypoglossal nerves decreased or eliminated the CTPP during swallowing. Elongation of the distal cervical esophagus increased basal circumferential cervical esophageal tension as well as the CTPP. Transecting the vagus or pharyngoesophageal nerves, or administering hexosamine intravenously, had no significant effect on CTPP. We conclude that CTPP is a response to esophageal elongation during laryngeal elevation during the pharyngeal phase of swallowing, which is not caused by muscle contraction or mediated by the nervous system. The CTPP may assist in the distal movement of boluses before activation of the esophageal phase of swallowing, and may serve to prevent esophagopharyngeal reflux. We hypothesize that the CTPP is a biomechanical decrease in elasticity of the circumferential connective tissue of the cervical esophagus caused by the stress of cervical esophageal elongation.NEW & NOTEWORTHY The pharyngeal phase of swallowing includes increased circumferential tension of the cervical esophagus during the pharyngeal phase of swallowing (CTPP). The CTPP is a biomechanical response caused by elongation of the esophagus during laryngeal elevation, and is not caused by muscle contraction or mediated by the nervous system. The CTPP may assist in the distal movement of boluses before activation of the esophageal phase of swallowing, and may serve to prevent esophagopharyngeal reflux.

Effects of chin tuck against resistance exercise on post-stroke dysphagia rehabilitation: A systematic review and meta-analysis

Background

Chin tuck against resistance (CTAR) exercise was introduced to substitute for the commonly used Shaker exercise for dysphagia rehabilitation. The effects of CTAR exercise in stroke survivors needs to be validated.

Objective

To investigate the effects of Chin tuck against resistance (CTAR) exercise on the swallowing function and psychological condition in stroke survivors compared to no exercise intervention and the Shaker exercise.

Materials and methods

The Cochrane Library, PubMed, Web of Science, EMBASE, CINAHL and four Chinese databases were searched for randomized controlled trails (RCTs) and quasi-RCTs from inception to February 2022.

Results

After screened and assessed the methodological quality of the studies, nine studies with 548 stroke survivors were included in the systematic review. 8 studies were included in the meta-analysis using RevMan 5.4 software. The mean difference (MD) or standardized mean difference (SMD) with 95% confidence intervals (CIs) were calculated. The results revealed that CTAR exercise is effective in improving swallowing safety (MD, -1.43; 95% CI, -1.81 to -1.06; P < 0.0001) and oral intake ability (SMD, -1.82; 95% CI, -3.28 to -0.35; P = 0.01) compared with no exercise intervention, CTAR exercise is superior to Shaker exercise in improving swallowing safety (MD, -0.49; 95% CI, -0.83 to -0.16; P = 0.004). The psychological condition in CTAR group is significant better than the control group (MD, -5.72; 95% CI, -7.39 to -4.05; P < 0.00001) and Shaker group (MD, -2.20; 95% CI, -3.77 to -0.64; P = 0.006).

Conclusions

Our findings support CTAR exercise as a superior therapeutic exercise for post-stroke dysphagia rehabilitation than Shaker exercise. More high-qualities RCTs from larger multicenter are needed to analysis the effects of CTAR exercise in patients with different type and phase of stroke and explore the optimal training dose.

Deglutition and the Regulation of the Swallow Motor Pattern

Despite centuries of investigation, questions and controversies remain regarding the fundamental genesis and motor pattern of swallow. Two significant topics include inspiratory muscle activity during swallow (Schluckatmung, i.e., "swallow-breath") and anatomical boundaries of the swallow pattern generator. We discuss the long history of reports regarding the presence or absence of Schluckatmung and the possible advantages of and neural basis for such activity, leading to current theories and novel experimental directions.

Use of the "ee" Maneuver in a Patient With Dysphagia Due to Severe Pseudobulbar Palsy

Dysphagia in pseudobulbar palsy is characterized by impairment of the oral stage of swallowing. The flow of the bolus from the oral cavity into the pharynx at the fauces may be blocked in some patients, which prevents the bolus flow by contact of the tongue with the palate. Herein, we demonstrated a case with pseudobulbar palsy who could deliver bolus from the oral cavity to the pharynx by vocalizing "ee." An 81-year-old man presented with a recurrent cerebral infarction due to cardiogenic embolism. He presented with pseudobulbar palsy and had severe dysphagia due to bilateral cerebral hemisphere lesions. On day 84, a videofluoroscopic examination of swallowing was performed in a 30° reclining posture. When the bolus reached the posterior part of the tongue in the oral cavity, the clinician asked the patient to say "ee." The base of the tongue moved forward and downward, and the anterior to the middle part of the tongue was elevated in the mouth. As a result, the fauces opened, the functional blockage was released, and the bolus flowed into the pharyngeal cavity. Shortly after the swallowing reflex, the bolus passed through the pharynx. We have named this swallowing maneuver the "ee" maneuver. The "ee" maneuver can be one of the swallowing methods to improve bolus transport from the oral cavity to the pharynx in patients with dysphagia and cognitive impairment due to pseudobulbar palsy.

The Effect of Sensory Level Versus Motor Level Electrical Stimulation of Pharyngeal Muscles in Acute Stroke Patients with Dysphagia: A Randomized Trial

Dysphagia is a serious cause of morbidity and mortality in stroke survivors. Electrical stimulation is often included as part of the treatment plan for dysphagia and can be applied at a sensory or motor level intensity. However, evidence to support these different modes of stimulation is lacking. This study compared the effectiveness of sensory and motor level stimulation on post-stroke dysphagia. This is a randomized trial conducted in an inpatient rehabilitation facility. Thirty-one participants who had dysphagia caused by stroke within 6 months prior to enrolment were included. Participants were excluded if they had a contraindication for electrical stimulation, previous stroke, psychiatric disorder, contraindications for modified barium swallow study (MBSS), or pre-morbid dysphagia. Each patient received ten sessions that included 45 min of anterior neck sensory or motor level electrical stimulation in addition to traditional dysphagia therapy. Motor stimulation was administered at an intensity sufficient to produce muscle contractions. Sensory stimulation was defined as the threshold at which the patient feels a tingling sensation on their skin. Swallow functional assessment measure (FAM), dysphagia outcome severity scale (DOSS), national outcome measurement system (NOMS), penetration aspiration scale (PAS), diet change, and the swallowing quality of life questionnaire (SWAL-QOL). Clinical outcomes were analyzed using a Wilcoxon signed-rank test, Mann–Whitney U test, RM ANOVA, or chi-square analysis. There was no significant difference in age, length of stay, or initial swallow FAM between groups. Patients in the sensory group showed significant improvement on swallow FAM, DOSS, and NOMS, while those in the motor group did not (Sensory: Swallow FAM (S = 48, p = 0.01), DOSS (S = 49.5, p = 0.001), NOMS (S = 52.5, p = 0.006); Motor: Swallow FAM (S = 20.5, p = 0.2), DOSS (S = 21, p = 0.05), NOMS (S = 29.5, p = 0.2)). When the groups were combined, there was statistically significant improvement on all measures except the PAS (Swallow FAM (S = 138.5, p = 0.003), DOSS (S = 134.5, p < 0.001), NOMS (S = 164, p = 0.0004)). When comparing motor to sensory NMES, there was no significant difference between groups for Swallow FAM (p = .12), DOSS (p = 0.52), or NOMS (p = 0.41). There was no significant difference in diet change for solid food or liquids among the groups, although 50% more participants in the sensory group saw improvement in diet. This study supports the use of electrical stimulation as part of the treatment plan for post-stroke dysphagia. Sensory-level stimulation was associated with greater improvement on outcome measures compared to motor level stimulation.

Swallowing function in the chronic stage following stroke is associated with white matter integrity of the callosal tract between the interhemispheric S1 swallowing representation areas

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Swallowing performance was tested in dysphagic patients following stroke.

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M1 and S1 callosal tracts relevant for swallowing was mapped in the HCP-dataset.

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S1 and M1 swallowing tracts were overlapping between in house and HCP datasets.

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Swallowing specific callosal tracts showed lower FA for patients compared to HCs.

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Integrity of S1 callosal fibres (FA) was associated with swallowing performance.

Sensorimotor representations of swallowing in pre- and postcentral gyri of both cerebral hemispheres are interconnected by callosal tracts. We were interested in (1) the callosal location of fibers interconnecting the precentral gyri (with the primary motor cortex; M1) and the postcentral gyri (with the primary somatosensory cortex; S1) relevant for swallowing, and (2) the importance of their integrity given the challenges of swallowing compliance after recovery of dysphagia following stroke. We investigated 17 patients who had almost recovered from dysphagia in the chronic stage following stroke and age-matched and gender-matched healthy controls. We assessed their swallowing compliance, investigating swallowing of a predefined bolus in one swallowing movement in response to a ‘go’ signal when in a lying position. A somatotopic representation of swallowing was mapped for the pre- and postcentral gyrus, and callosal tract location between these regions was compared to results for healthy participants. We applied multi-directional diffusion-weighted imaging of the brain in patients and matched controls to calculate fractional anisotropy (FA) as a tract integrity marker for M1/S1 callosal fibers. Firstly, interconnecting callosal tract maps were well spatially separated for M1 and S1, but were overlapped for somatotopic differentiation within M1 and S1 in healthy participants’ data (HCP: head/face representation; in house dataset: fMRI-swallowing representation in healthy volunteers). Secondly, the FA for both callosal tracts, connecting M1 and S1 swallowing representations, were decreased for patients when compared to healthy volunteers. Thirdly, integrity of callosal fibers interconnecting S1 swallowing representation sites was associated with effective swallowing compliance. We conclude that somatosensory interaction between hemispheres is important for effective swallowing in the case of a demanding task undertaken by stroke survivors with good swallowing outcome from dysphagia.

Excitatory neurons in paraventricular hypothalamus contributed to the mechanism underlying acupuncture regulating the swallowing function

Paraventricular hypothalamus (PVH) is demonstrated to regulate stress, feeding behaviors, and other related homeostatic processes. However, no direct evidence has been investigated for the role of PVH in swallowing function. Acupuncture therapy at Lianquan (CV23) acupoint has been reported to improve the swallowing function in clinical trials, but its underlying mechanism still needs to be uncovered. Thus, we aimed to explore whether PVH involved the acupuncture mediated regulating swallowing function. Chemogenetics, electromyography (EMG) recording, and immunofluorescence staining methods were combined to demonstrate that neurons in PVH could be activated by electroacupuncture (EA) stimulation at CV23, and this neuronal cluster was represented as excitatory neurons. Furthermore, we mapped both the inputs and outputs of PVH neurons using viral tracing. The neurons in PVH projected with the brain regions, including parabrachial nucleus (PBN) and the solitary tract nucleus (NTS), which both participated in the swallowing process. The EA function regulating the swallowing was attenuated after inhibiting the neurons in PVH in the post stroke dysphagia. In conclusion, this study suggested that EA at CV23 could regulate swallowing function involving the excitatory neurons in PVH.

Migratory pharyngeal foreign bodies and related complications: Analysis of 20 cases

PURPOSE

To explore the diagnostic approach and therapeutic method of migratory pharyngeal foreign bodies and related complications, to improve the understanding of such disease and to reduce misdiagnosis and missed diagnosis.

MATERIAL AND METHODS

A retrospective study was performed by collecting patients who were treated because of the related complications caused by migratory pharyngeal foreign bodies from 2012 to 2020.

RESULTS

A total of 20 patients were admitted to hospital due to the related complications. 14 cases showed cervical mass; 3 cases showed abscess of the mouth floor; 1 cases showed retropharyngeal abscess; 1 cases showed laryngeal granuloma; 1 cases showed mass of tongue. All patients received imaging examination of B-ultrasonography or computed tomography (CT). 19 patients were treated by surgery, and 1 patient was taken conservative treatment. All foreign bodies was successfully removed. As for the type of foreign bodies, there have 15 cases of fishbone, 2 cases of crabshell, 2 cases of shrimp shell, 1 cases of duck bone.

CONCLUSIONS

Migrating foreign bodies and related complications are rare in clinic, much attention should be paid to avoid missed diagnosis or misdiagnosis.

Pharyngo-Esophageal Modulatory Swallow Responses to Bolus Volume and Viscosity Across Time

Objectives/Hypothesis

Modulation of the pharyngeal swallow to bolus volume and viscosity is important for safe swallowing and is commonly studied using high‐resolution pharyngeal manometry (HRPM). Use of unidirectional pressure sensor technology may, however, introduce variability in swallow measures and a fixed bolus administration protocol may induce time and order effects. We aimed to overcome these limitations and to investigate the effect of time by repeating randomized measurements using circumferential pressure sensor technology.

Study Design

Sub‐set analysis of data from the placebo arm of a randomized, repeated measures trial.

Methods

HRPM with impedance was recorded using a solid‐state catheter with 36 circumferential pressure sensors and 18 impedance segments straddling from hypopharynx to stomach. Testing included triplicates of 5, 10, and 20 ml thin liquid and 10 ml thick liquid boluses, the order of the thin liquid boluses was randomized. The swallow challenges were repeated approximately 10 minutes after finishing the baseline measurement.

Results

We included 19 healthy adults (10/9 male/female; age 24.5 ± 4.1 year). Intrabolus pressure, all upper esophageal sphincter (UES) opening and relaxation metrics, and flow timing metrics increased with larger volumes. A thicker viscosity decreased UES relaxation time, UES basal pressure, and flow timing metrics, whereas UES opening extent increased. Pre‐swallow UES basal pressure and post‐swallow UES contractile integral decreased over time.

Conclusion

Using circumferential pressure sensor technology, the effects of volume and viscosity were largely consistent with previous reports. UES contractile pressures reduced over time. The growing body of literature offers a benchmark for recognizing aberrant pharyngo‐esophageal motor responses.

Level of Evidence

3 Laryngoscope, 132:1817–1824, 2022

Cross-Sectional Study of Swallowing Phases in Cases of Megaesophagus Caused by Chagas Disease

Background

Chagas disease, caused by the flagellate protozoan Trypanosoma cruzi, is an infectious cause of secondary achalasia and megaesophagus. Moreover, the oral and pharyngeal phases of swallowing may also be affected, which may contribute to dysphagia and increase the possibility of airway aspiration during and/or after swallowing. This cross-sectional study evaluated, with videofluoroscopy, the oral, pharyngeal, and esophageal phases of swallowing in patients with megaesophagus caused by Chagas disease. The hypothesis is that there is impairment of the pharyngeal phase of swallowing that may increase the risk of airway aspiration.

Methods

A total of 29 patients, aged 48 - 73 years (mean: 63.8 ± 5.1 years), with dysphagia, radiological changes in the esophagus, and positive serologic test for Chagas disease, participated in the study. They were submitted to the videofluoroscopic evaluation of oral, pharyngeal, and esophageal phases, swallowing twice 10 mL of liquid and 10 mL of thickened barium boluses.

Results

The most frequent findings were: oral residues and ineffective ejection in the oral phase; residues in vallecula, pharynx, and pyriform sinuses in the pharyngeal phase; abnormal esophageal motility, longer clearance, and longer transit in the esophageal phase. Laryngeal penetration was seen in 28% of the patients. Patients with increased esophageal diameter had more pharyngeal residues than patients without increased esophageal diameter. None of the patients had airway aspiration.

Conclusion

Megaesophagus caused by Chagas disease may affect all phases of swallowing, with an increase in oral and pharyngeal residues which suggest the impairment of oral and pharyngeal efficiency. None of the patients had airway aspiration.

Gray and White Matter Correlates of Dysphagia in Progressive Supranuclear Palsy

BACKGROUND

Dysphagia is a common symptom of progressive supranuclear palsy often leading to aspiration pneumonia and death.

OBJECTIVE

The aim of this study was to examine how impairments of the oral and pharyngeal phases of the swallow and airway incursion during liquid swallows relate to gray and white matter integrity.

METHODS

Thirty-eight participants with progressive supranuclear palsy underwent videofluorographic swallowing assessment and structural and diffusion tensor head magnetic resonance imaging. Penalized linear regression models assessed relationships between swallowing metrics and regional gray matter volumes and white matter fractional anisotropy and mean diffusivity.

RESULTS

Oral phase impairments were associated with reduced superior parietal volumes and abnormal diffusivity in parietal and sensorimotor white matter, posterior limb of the internal capsule, and superior longitudinal fasciculus. Pharyngeal phase impairments were associated with disruption to medial frontal lobe, corticospinal tract, and cerebral peduncle. No regions were predictive of airway incursion.

CONCLUSIONS

Differential patterns of neuroanatomical impairment corresponded to oral and pharyngeal phase swallowing impairments. © 2021 International Parkinson and Movement Disorder Society.

Effects of remifentanil on pharyngeal swallowing and esophageal motility: no impact of different bolus volumes and partial antagonism by methylnaltrexone

Remifentanil impairs swallowing, and disturbed accommodation to bolus volume may be one of the underlying causes. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. So, this study aimed to investigate if remifentanil-induced swallowing dysfunction is dependent on the bolus volume and whether the effect of remifentanil could be counteracted by methylnaltrexone, a peripherally acting opioid antagonist. Nineteen healthy volunteers were included in this double-blinded, randomized, placebo-controlled, crossover study. Study participants received target-controlled remifentanil infusions and placebo infusions in a randomized order. Methylnaltrexone was administered by intravenous injection of doses of 0.3 mg/kg. Recordings of pressure and impedance data were acquired using a combined manometry and impedance solid-state catheter. Data were analyzed from three series of bolus swallows, baseline, during study medication exposure, and 15 min after methylnaltrexone. Remifentanil induced significant effects on multiple pharyngeal and esophageal function parameters. No significant differences in remifentanil-induced swallowing dysfunction related to different bolus volumes were found. Pharyngeal effects of remifentanil were not significantly counteracted by methylnaltrexone, whereas on the distal esophageal level, effects on distension pressures were counteracted. Changes in pharyngeal and esophageal pressure flow variables were consistent with previous results on remifentanil-induced swallowing dysfunction and uniform across all bolus volumes. The effects of remifentanil on the pharyngeal level and on the proximal esophagus appear to be predominantly centrally mediated, whereas the effects of remifentanil on the distal esophagus may be mediated by both central and peripheral mechanisms.NEW & NOTEWORTHY In this randomized controlled trial, we used the "Swallow Gateway" online platform to analyze the effects of remifentanil on pharyngeal and esophageal swallowing. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. By using methylnaltrexone, we demonstrated that effects of remifentanil on pharyngeal swallowing were predominantly centrally mediated, whereas its effects on the distal esophagus may be mediated by both central and peripheral mechanisms.

Serial evaluation of swallowing function in a long-term survivor of V180I genetic Creutzfeldt-Jakob disease

Swallowing function in long-term survivors with Creutzfeldt-Jakob disease (CJD) remains unknown. Herein, we demonstrated serial evaluation of swallowing function in a case with V180I genetic CJD (gCJD) using videofluoroscopic examination of swallowing (VF). A 69-year-old woman was admitted to our hospital because of bradykinesia and memory disturbances 4 months after the onset of symptoms. Neurological examination revealed dementia, bradykinesia and frontal signs. Diffusion-weighted MRI revealed bilateral cortical hyperintensity in the frontal, temporal, and parietal cortices, and PRNP gene analysis indicated a V180I mutation. Her dysphagia gradually progressed, and she received percutaneous gastrostomy 42 months after the onset. VF was performed at 27, 31, 39, and 79 months after the onset. Although bolus transport from oral cavity to pharynx gradually worsened and initiation of the pharyngeal swallow was gradually delayed, the pharyngeal swallowing function was preserved even at 72 months after onset. MRI revealed no apparent atrophy of brainstem, and single photon emission computed tomography showed preserved regional cerebral blood flow in the brainstem. These findings suggest that the pathophysiology of dysphagia in a long-term survivor of V180I gCJD is that of pseudobulbar palsy, likely owing to preserved brainstem function even in the akinetic mutism state.

Risk Factors for Dysphagia and the Impact on Outcome After Spontaneous Subarachnoid Hemorrhage

Background

Despite the tremendous impact of swallowing disorders on outcome following ischemic stroke, little is known about the incidence of dysphagia after subarachnoid hemorrhage (SAH) and its contribution to hospital complications, length of intensive care unit stay, and functional outcome.

Methods

This is a retrospective analysis of an ongoing prospective cohort study. Swallowing ability was assessed in consecutive non-traumatic SAH patients admitted to our neurological intensive care unit using the Bogenhausen Dysphagia Score (BODS). A BODS > 2 points indicated dysphagia. Functional outcome was assessed 3 months after the SAH using the modified Rankin Scale with a score > 2 defined as poor functional outcome.

Results

Two-hundred and fifty consecutive SAH patients comprising all clinical severity grades with a median age of 57 years (interquartile range 47–67) were eligible for analysis. Dysphagia was diagnosed in 86 patients (34.4%). Factors independently associated with the development of dysphagia were poor clinical grade on admission (Hunt & Hess grades 4–5), SAH-associated parenchymal hematoma, hydrocephalus, detection of an aneurysm, and prolonged mechanical ventilation (> 48 h). Dysphagia was independently associated with a higher rate of pneumonia (OR = 4.32, 95% CI = 2.35–7.93), blood stream infection (OR = 4.3, 95% CI = 2.0–9.4), longer ICU stay [14 (8–21) days versus 29.5 (23–45) days, p < 0.001], and poor functional outcome after 3 months (OR = 3.10, 95% CI = 1.49–6.39).

Conclusions

Dysphagia is a frequent complication of non-traumatic SAH and associated with poor functional outcome, infectious complications, and prolonged stay in the intensive care unit. Early identification of high-risk patients is needed to timely stratify individual patients for dysphagia treatment.

Electronic supplementary material

The online version of this article (10.1007/s12028-019-00874-6) contains supplementary material, which is available to authorized users.

Chin tuck against resistance exercise for dysphagia rehabilitation: A systematic review

BACKGROUND

Chin tuck against resistance (CTAR) exercise has been recently reported to be a new therapeutic exercise method that can help improve swallowing function in patients with dysphagia. However, due to the differences in exercise protocols, methods and the tools used across studies of CTAR exercise, an overall systematic review of these studies is necessary.

OBJECTIVE

The present study investigated the exercise protocols, methods and tools used in various studies of CTAR exercise and summarised their findings.

METHODS

We searched for studies related to CTAR exercise using electronic databases and selected nine articles for review. The articles were categorised on the basis of four criteria: study design and quality, training protocol, outcome measures and clinical effect.

RESULTS

Four articles reported that CTAR exercise not only helped activate the suprahyoid muscle in healthy adults, but also activated the sternocleidomastoid muscle less than Shaker exercise. In addition, five articles reported that CTAR exercise was effective in improving swallowing function and oral diet stage in the pharyngeal phase, including reduction of airway aspiration in patients with dysphagia after stroke.

CONCLUSIONS

CTAR exercise more selectively activates the suprahyoid muscle and is an effective therapeutic exercise for improving swallowing function in patients with dysphagia. Because it is less strenuous than Shaker exercise, it requires less physical burden and effort, allowing greater compliance.

Long-term preservation of pharyngeal swallowing function in MM2-cortical-type sporadic Creutzfeldt-Jakob disease

Swallowing function in long-term survivors of Creutzfeldt-Jakob disease (CJD) has not been elucidated. Herein, we report a patient with MM2-cortical-type sporadic CJD (MM2C-type sCJD) with long-term preservation of pharyngeal swallowing function using videofluoroscopic (VF) examination of swallowing. A 55-year-old woman was admitted to hospital because of dyscalculia and memory disturbance 3 years after the onset of these symptoms. Neurological examination revealed dementia, extrapyramidal signs, and delusion. Diffusion-weighted MRI revealed bilateral hyperintensity in the basal ganglia and frontal, temporal, and parietal cortices. No mutation with the methionine homozygote at codon 129 was found on PRNP gene analysis. VF was performed 68 months after the onset. Although bolus transport from the oral cavity to the pharynx worsened, the pharyngeal swallowing function was preserved even 68 months after onset. Serial MRI examinations revealed no apparent atrophy of the brainstem. Single photon emission computed tomography revealed that the regional cerebral blood flow in the brainstem was preserved. These findings suggest that pseudobulbar palsy is the pathophysiology underlying dysphagia in long-term survivors of MM2C-type sCJD, probably owing to preserved brainstem function even in a state of akinetic mutism.

The level of impaired esophageal bolus transit measured by multichannel intraluminal impedance: Cross-sectional study

BACKGROUND

Esophageal motility disorders (EMDs) are often diagnosed manometrically, yet the underlying pathology is not always clear. Esophageal function testing (EFT), which incorporates manometry and multichannel intraluminal impedance (MII), is considered a useful tool in the assessment of EMDs.

OBJECTIVE

This study aims to assess the most likely level of impaired bolus transit within the esophagus which may help further localize and characterize EMDs.

METHODS

In a retrospective study design, we reviewed consecutive EFTs over a period of 12 months. Data included diagnosis, presenting symptoms, and EFT results of liquid and viscous swallows. Each patient underwent 10 liquid and 10 viscous swallows, and bolus transit is measured at 5, 10, 15 and 20 cm above the gastroesophageal junction (GEJ). We recorded the initial level of impaired bolus transit for each swallow.

RESULTS

A total of 2358 swallows in 118 patients was included for analysis. Of these, 837 swallows (35.5%) were incompletely transmitted. The proportions of impaired bolus transit were 39%, 41%, 15.6%, 4.4% at 20 cm, 15 cm, 10 cm, and 5 cm above the GEJ, respectively. The common symptoms at presentation were dysphagia (47%), heartburn (44%), chest pain (24.6%) and regurgitation (18%). The mean lower esophageal sphincter (LES) pressure was 24 ± 13.9 mmHg whereas the mean contraction amplitude was 84 ± 46.6 mmHg.

CONCLUSION

In patients with abnormal esophageal clearance, the most likely levels of impaired bolus transit are 15 and 20 cm above the GEJ. These levels of the esophagus should be a focus of attention in future studies evaluating the pathophysiology of esophageal dysmotility.

A retrospective cross-sectional analysis of swallowing and tongue functions in maxillectomy patients

PURPOSE

To investigate the profiles of swallowing and tongue functions, and to identify factors influencing swallowing in maxillectomy patients.

METHODS

Maxillectomy patients whose swallowing function defined by Eating Assessment Tool (EAT-10) score and tongue functions (oral diadochokinesis: ODK, maximum tongue pressure: MTP) with or without obturator prostheses had been evaluated were enrolled in this study. The effects of the history of radiotherapy and soft palate defect on swallowing function were evaluated. The effect of radiotherapy on oral dryness was also evaluated. To examine correlations of swallowing function with continuous variables, Spearman correlation coefficients were calculated.

RESULTS

A total of 47 maxillectomy patients (23 males and 24 females, median age: 71 [IQR: 63-76]) were registered. The median value of EAT-10 scores was 3 [IQR: 0-14]. Patients with the history of radiotherapy, but not with soft palate defect, showed significantly declined swallowing function. ODK and MTP of patients wearing obturator prostheses were significantly improved. No significant effect of radiotherapy on oral dryness was found. A significant correlation was found between EAT-10 score and MTP (P = 0.04).

CONCLUSIONS

Swallowing function in maxillectomy patients was relatively impaired and the patients with the history of radiotherapy showed lower swallowing function. Obturator prostheses could contribute to the improvement of MTP and ODK (/ta/). MTP may play a crucial role in swallowing in maxillectomy patients.

Medical aromatherapy in geriatric syndrome

Geriatric syndromes are symptoms and signs, such as falls, incontinence, delirium, pressure ulcers, dysphagia and so on, that often threaten the independence of older adults, rather than the disease itself. Although the syndromes are very common in older people, it is difficult to treat those by modern medicine due to their complexity. To mitigate the intractable geriatric symptoms, we review the efficacy of aromatherapy, especially for dysphagia, dyspnea, cognitive dysfunction and falls in geriatric syndrome. Olfactory stimulation using a volatile black pepper oil on institutional residents improved the swallowing reflex, which is a crucial risk factor of aspiration pneumonia. Brain imaging study showed that olfactory stimulation using volatile black pepper oil activated cerebral regions of the anterior cingulate and the insular cortex, which play a role in controlling appetite and swallowing. Also, aromatherapy with volatile l-menthol decreased the sense of dyspnea and improved the efficacy of exercise therapy. The fragrance of the combination of rosemary and lemon oils in the morning, and the combination of lavender and orange oils in the night-time were reported to improve cognition and behavioural and psychological symptoms of dementia, respectively. Also, the combination of lavender and lemon balm oils was reported to be effective for irritability-related agitation in older adults. Furthermore, aromatherapy with lavender fragrance could improve both static and dynamic balance, resulting in a reduction in the number of fallers and the incidence rate in older people. Thus, aromatherapy is a promising remedy for geriatric syndrome. Geriatr Gerontol Int 2021; 21: 377-385.

Vertebrate Evolution Conserves Hindbrain Circuits despite Diverse Feeding and Breathing Modes

Feeding and breathing are two functions vital to the survival of all vertebrate species. Throughout the evolution, vertebrates living in different environments have evolved drastically different modes of feeding and breathing through using diversified orofacial and pharyngeal (oropharyngeal) muscles. The oropharyngeal structures are controlled by hindbrain neural circuits. The developing hindbrain shares strikingly conserved organizations and gene expression patterns across vertebrates, thus begs the question of how a highly conserved hindbrain generates circuits subserving diverse feeding/breathing patterns. In this review, we summarize major modes of feeding and breathing and principles underlying their coordination in many vertebrate species. We provide a hypothesis for the existence of a common hindbrain circuit at the phylotypic embryonic stage controlling oropharyngeal movements that is shared across vertebrate species; and reconfiguration and repurposing of this conserved circuit give rise to more complex behaviors in adult higher vertebrates.

Prevalence and Risk Factors of Dysphagia in Patients with Multiple Sclerosis

Dysphagia is one of the most common symptoms in multiple sclerosis (MS) patients. It can reduce the quality of life and increase the risk of mortality by developing complications such as aspiration pneumonia. The present study was conducted to estimate the prevalence of dysphagia in MS patients and investigate the associations between dysphagia and disease characteristics. The Persian version of the DYMUS questionnaire was used to assess dysphagia in 865 patients with MS, including 738 (85.3%) relapsing-remitting MS (RRMS), 106 (12.3%) secondary progressive MS (SPMS), and 21 (2.4%) primary progressive MS (PPMS). Also, demographic and clinical data, including age, sex, smoking status, Expanded Disability Status Scale (EDSS) score, disease duration, disease-modifying therapies exposure, initial symptoms of MS, were recorded. The mean (SD) age was 37.95(9.25) years, and 83.1% of the participants were female. The prevalence of dysphagia was estimated to be 25.4% among all patients. According to the DYMUS questionnaire results, the prevalence of dysphagia in RRMS, SPMS, and PPMS patients was 22.2%, 44.3%, and 42.9%, respectively. After multivariate analysis the current EDSS score (OR = 1.197, CI: 1.062, 1.350, p = 0.003), cerebellar impairment (OR = 1.335, CI: 1.450, 4.716, p = 0.004) and motor dysfunction (OR = 1.651, CI: 1.004, 2.715, p = 0.048) emerged as the risk factors for dysphagia. Since dysphagia, as previously mentioned, is a common symptom in multiple sclerosis, particularly in SPMS and PPMS courses, active screening for this condition is recommended in all patients, particularly those with identified risk factors.

Biomechanical correlates of sequential drinking behavior in aging

BACKGROUND

The timed water swallow test (TWST) is a test of sequential swallowing where a measured volume is ingested as quickly as comfortably possible. We undertook a study of the biomechanics underpinning the TWST in healthy young and older participants.

METHODS

Thirty healthy volunteers underwent high-resolution impedance manometry (MMS; Unisensor, 2.7 mm diameter, 32 pressure sensors, 16 impedance segments). Participants were asked to drink 150 mL, 0.9% normal saline solution rapidly. Swallowing biomechanics and bolus flow characteristics were assessed using pressure-flow analysis and compared using t test and Fisher's exact test with significance as P < .05.

KEY RESULTS

Older participants (n = 18; 76 ± 11 years) took longer to complete the TWST (21.2 ± 2.5 vs 9.2 ± 1.0 seconds; P < .001) and displayed reduced volume per swallow (16.6 ± 1.3 vs 27.8 ± 2.9 mL; P < .001) compared to younger participants (n = 12; 29 ± 5 years). Two distinctive pharyngeal swallowing patterns were observed: (a) a single rapid sequence of swallows with or without a clearing swallow (Pattern I) or (b) multiple, shorter sequences interrupted and/or interspersed with single swallows or breaks (Pattern II). Some older participants showed biomechanical evidence of upper esophageal sphincter restriction (n = 7) or impaired deglutitive inhibition (n = 7), associated with the more prolonged Pattern II (TWST duration 30.1 ± 1.5 vs Pattern I 11.9 ± 1.5 seconds; P < .001).

CONCLUSIONS AND INFERENCES

Healthy older participants had an increased duration of TWST, suggesting a need to adapt normative values for this population. Rapid sequential swallowing was associated with evidence of UES restriction and impaired deglutitive inhibition in some older participants.

Esophageal Peristalsis Disorders in ALS Patients with Dysphagia

To detect the variations of esophageal peristalsis in amyotrophic lateral sclerosis (ALS) patients with predominantly bulbar or predominantly pseudobulbar clinical presentation by using esophageal manometry (EM). Fifteen ALS patients with pseudobulbar clinical presentation (PBP) and 13 patients with bulbar presentation (BP), fulfilling WFN Criteria, were studied. EM was performed in all subjects using a flexible catheter with solid-state transducers. Swallowing was initiated with 5 to 10 mL of water (wet swallows) and saliva (dry swallows) and repeated at 30 s intervals. The manometric parameters were measured automatically and visualized by the computer system. The tracings were analyzed using Synectics software. In PBP patients, an increase of resting pressure value in the upper esophageal sphincter (UES) >45 mmHg, a wave-like course of resting pressure, and toothed peristaltic waves were observed. In BP patients, a low amplitude of peristaltic waves <30 mmHg (mean: 17 ± 5) was recorded, without signs of esophageal motility disturbance at onset or during progression. EM procedure allows objectively distinguishing dysphagia in ALS patients due to bulbar syndrome from the dysphagia due to pseudobulbar syndrome. It is important to identify PBP patients because of their high risk of aspiration.